Regional high-density mapping of the atrial fibrillation substrate

1. A method for identifying target areas of a heart of a patient likely to be involved in a perpetuation of atrial fibrillation (AF), comprising: taking a plurality of local recordings of the heart of the patient during a measurement window, each local recording corresponding to an area of the heart of the patient, each local recording comprising at least two local electrograms (EGMs) and at least two base lines, the method further comprising obtaining a reference cycle of an arrhythmia, the reference cycle being an average duration of a first reference base line and a second reference base line between a first local reference EGM and a second local reference EGM of a local recording corresponding to a healthy area of the heart of the patient, and for each local recording: determining an average duration of a first base line and a second base line between a first local EGM and a second local EGM; calculating at least one ratio out of: an average ratio of the average duration of the first base line and the second base line to the reference cycle of the arrhythmia; a median ratio of the average duration of the first base line and the second base line to the reference cycle of the arrhythmia; for each base line, a ratio of the duration of the base line to the reference cycle of the arrhythmia; classifying the corresponding area of the heart according to the corresponding area's degree of involvement in the perpetuation of the AF, the degree of involvement of the area being a function of the ratio or ratios calculated; and generating and displaying a map of the heart of the patient on which the classified areas of the heart are formed.

2. The method as claimed in claim 1 , in which an area is classified as a non-target area if the average ratio, the median ratio, or all the ratios calculated are greater than or equal to a first value, the area otherwise being classified as a true or a false positive target area.

3. The method as claimed in claim 2 , in which an area is classified as true or a false positive priority target area if the average ratio, the median ratio, or at least one ratio calculated f is less than or equal to a second value.

4. The method as claimed in claim 3 , in which an area is classified as a true or a false positive secondary target area if the average ratio, the median ratio, or at least one ratio calculated lies between the second value and a third value lying between the first and second values; and the area is classified as a true or false positive tertiary target area if the average ratio, the median ratio, or at least one ratio calculated lies between the third value and the first value.

5. The method as claimed in claim 1 , in which the classification of each of the areas of the heart is also a function of a repetition in the corresponding local recording of the calculated ratio base lines of repetitive values; a target area being a true positive if the repetition corresponding to the ratio value having led to the classification of the area as being a target area is proven.

6. The method as claimed in claim 1 , in which the classification of each area of the heart is also a function of an average of amplitude values of depolarizations of the corresponding local recording; a target area being a true positive if the average of the amplitude values is less than a given threshold value.

7. The method as claimed in claim 1 , in which the classification of each of the areas of the heart is also a function of a repetition in the corresponding local recording of the base lines with calculated ratio of repetitive values and a function of an average of amplitude values of depolarizations of the corresponding local recording; a target area being a true positive if the repetition is proven and if the average of the amplitude values is greater than a given threshold value.

8. The method as claimed in claim 1 , further comprising, for at least some of the local recordings of the heart: obtaining at least one regional recording from a plurality of local recordings corresponding to adjacent areas, the adjacent areas forming a region corresponding to the regional recording, the local recordings not exhibiting any identifiable base line being discarded, so the regional recording comprises at least one regional EGM; and for each regional recording: determining an average duration of a first regional base line and a second regional base line between a first regional EGM and a second regional EGM; calculating at least one ratio out of: an average ratio of the average duration of the first regional base line and the second regional base line to the reference cycle of the arrhythmia; and for each base line, a ratio of the duration of the base line to the reference cycle of the arrhythmia; and classifying the corresponding region of the heart according to its degree of involvement in perpetuation of the AF, the degree of involvement of the region being a function of the ratio or ratios calculated; the other steps of the method being carried out by replacing: local recording by regional recording and area by region.

9. A method for identifying target areas of a heart of a patient likely to be involved in a perpetuation of atrial fibrillation according to claim 1 , comprising an apparatus for identifying areas of the heart likely to be involved in the perpetuation of atrial fibrillation, comprising a digital analyzer and a digital mapper, wherein the digital analyzer implements the method as claimed in claim 1 ; the digital mapper being capable of generating a map of the heart of the patient on which the classification of the areas of the heart is formed.

10. A computer program comprising a series of instructions which implement the steps of: obtaining a reference cycle, determining an average duration of a first base line and a second base line between a first local EGM and a second local EGM, calculating at least one of the ratios, and classifying the corresponding area according to the method of claim 1 , executed by a processor.

11. A non-transient and computer-readable storage medium comprising a computer program as claimed in claim 10 .

12. A method for identifying target regions of a heart of a patient likely to be involved in a perpetuation of atrial fibrillation (AF), comprising: taking a plurality of regional recordings of the heart of the patient during a measurement window, each regional recording corresponding to a region of the heart of the patient combining a plurality of areas, the method further comprising: obtaining a reference cycle of an arrhythmia, the reference cycle being an average duration of a first base line and a second base line between a first depolarization and a second depolarization of a local recording corresponding to a healthy area of the heart of the patient; and for each regional recording: determining an average duration of a first base line and a second base line between the first depolarization and the second depolarizations of the regional recordings; calculating at least one ratio out of: an average ratio of the average duration of the first base line and the second base line to the reference cycle of the arrhythmia; for each base line, a ratio of the duration of the base line to the reference cycle of the arrhythmia; classifying the corresponding region of the heart according to its degree of involvement in the perpetuation of the AF, the degree of involvement of the region being a function of the ratio or ratios calculated; and generating and displaying a map of the heart of the patient on which the classified areas of the heart are formed.

13. The method as claimed in claim 12 , in which a region is classified as a non-target region if the average ratio or if all the ratios calculated is/are greater than or equal to a first value, the region being otherwise classified as a true or false positive target region.

14. The method as claimed in claim 13 , in which a region is classified as a true or false positive priority target region if the average ratio or at least one ratio calculated is less than or equal to a second value.

15. The method as claimed in claim 14 , in which a region is classified as a true or false positive secondary target region if the average ratio or at least one ratio calculated lies between the second value and a third value lying between the first and second values; and the region is classified as a true or false positive tertiary target region if the average ratio or at least one ratio calculated lies between the third value and the first value.

16. The method as claimed in claim 12 , in which the classification of each of the regions of the heart is also a function of a repetition in the corresponding regional recording of the base lines with calculated ratio of repetitive values; a target region being a true positive if the repetition is proven.

17. The method as claimed in claim 12 , in which the classification of each of the regions of the heart is also a function of an average of amplitude values of depolarizations of the corresponding regional recording; a target region being a true positive if the average of the amplitude values is less than a given threshold value.

18. The method as claimed in claim 12 , in which the classification of each of the regions of the heart is also a function of a repetition in the corresponding regional recording of the base lines with calculated ratio of repetitive values and a function of an average of amplitude values of depolarizations of the corresponding regional recordings; a target region being a true positive if the repetition is proven and if the average of the amplitude values is greater than a given threshold value.